Add dynamic dropdown list on Laravel 5.2 registration

i wanna add dynamic drop down list on my registration page but i don't know how to do it cause i'm new with laravel.

I don't know where to start.

i want to put 2 drop down list on registration form

we get the value from a table

first is "group" group consist of : 1. Administrator 2. Users 3. Guest

second is "department" (disabled) if the first drop down is Administrator or Guest, the second drop down disable. But if we choose Users, then the department drop down enable and get the data from department table.